The effect of ispaghula (Fybogel and Metamucil) and guar gum on glucose tolerance in man.

The effects of incorporating Fybogel (3.5 and 7 g doses), Metamucil (7 g) or guar gum (2.5 and 14.5 g doses) in a drink containing 50 g glucose on plasma glucose, plasma insulin and gastric emptying were studied in thirty-eight normal volunteers. In addition, the effects of Fybogel (7 g) on glucose tolerance, plasma insulin and gastric emptying were measured in fourteen non-insulin-dependent diabetics. Both doses of guar gum significantly lowered plasma glucose and plasma insulin responses to the oral glucose load in normal subjects, although 14.5 g guar gum did not delay the half-time for gastric emptying. Neither Fybogel nor Metamucil had significant effects on plasma glucose responses in normal subjects. In addition, Fybogel (at either dose) had no significant effects on plasma insulin levels, or on gastric emptying in normal subjects or on plasma glucose and insulin responses in diabetic patients. The viscosity of ispaghula solutions ( Fybogel ) was lower than that of guar gum solutions.